The oral sodium phosphate bowel preparation used in colonoscopies has been shown to cause kidney damage and long term renal failure, especially in elderly patients. Colonoscopy and flexible sigmoidoscopy are currently the most commonly used procedures for colon cancer screening and detection. Patients use a bowel cleansing agent the day prior to improve the diagnostic effectiveness of the procedure. Oral sodium phosphate solution (OSPS), oral sodium phosphate tablets (OSPT), and polyethylene glycol solutions (PEG) are the commonly used preparations because of their ease of use and their safety profile. Because an increasing number of patients are believed to have acute kidney injury from the use of OSPS and OSPT as bowel cleansing agents, the Food and Drug administration (FDA) issued a Black Box warning recommending that OSPS preparations should be used with caution in patients with impaired renal function. Case reports of acute renal failure in patients with presumably normal renal function are now being reported. Data suggests that elderly white women may be at increased risk. Whether this is true in the general population or is a selection bias based on the higher probability of this subset population undergoing screening colonoscopy procedures is unknown. There is a belief that in addition to causing AKI, OSPS and OSPT may also cause a chronic decline in renal function that might not be recognized and possibly not associated with OSPS or OSPT as causative agents.